Clinical relevance: Measuring reading ability is a crucial part of assessing patients who complain of reduced vision. Foreign language versions of such charts need to be developed and validated.
Background: It is difficult to measure or predict Korean reading ability due to a lack of a representative reading charts in Korean, and previous charts have limited capacity to detect deficits in reading ability among Korean patients with eye diseases.
Methods: Two printed versions of the reading chart were created. Thirty-four patients with no change in vision in the last three months and no expected change in vision in the next four weeks were included in this study. The results were validated by testing 13 normal-sighted adults (group 1), 14 patients with various macular diseases whose visual acuity was equal or better than 0.5 logarithm of the minimum angle of resolution (logMAR) (group 2), and seven patients with various macular diseases whose visual acuities were between 1.3 logMAR and 0.5 logMAR (group 3). Inter-chart and intra-subject repeatabilities were assessed for maximum reading speed (MRS) and critical print size (CPS).
Results: A total of 38 sentences were tested on 34 adults in three groups. Groups 1 and 2 did not differ significantly in terms of MRS and CPS. The MRS was lower in group 3, for each chart and between visits. The CPS was larger in group 3, for each chart and between visits, with the exception of chart 2 during visit one. With regard to test-retest reliability, the intraclass correlation co-efficients (ICCs) for chart 1 and chart 2 were more than 0.900. With regard to inter-chart reliability, the ICCs were more than 0.892, respectively.
Conclusion: The reading chart developed in this study was reliable in producing consistent results among a normal Korean population and patients with various macular diseases.
Keywords: Korea; reading acuity; reading chart; reading speed.